For the harvesting of whole plants with a field chopper, essentially two types of harvesting attachments are available at present.
On the one hand, cutting mechanisms for cuttings are used as harvesting attachments ahead of field choppers, so as to cut off relatively soft plants which are not excessively large, such as grass and unripe cereal, and to take them to the field chopper, in which they are chopped and transferred to the transporting vehicle. As a rule, the chopped plants are used as whole plant silage for the feeding of cattle or they are used in biogas systems. Such cutting mechanisms for cuttings usually comprise a number of mowing drums or mowing disks, which are arranged laterally, next to one another, for the cutting off of crops, and a transverse conveyor in the rear, which conveys the crops to the middle of the cutting mechanism for cuttings, and from there they are taken by a delivery conveyor to the rear and to the intake channel of the field chopper. As a rule, the driving of the mowing drums or mowing disks is carried out by gears located on the front side of the cutting mechanism for cuttings, which extend, as with mowing mechanisms—see U.S. Pat. No. 8,695,316 B2—on the front side of the cutting mechanism in the transverse direction. The transverse conveyor is usually a screw conveyor whose middle area is used as a delivery conveyor (U.S. Pat. No. 8,806,844 B2), or belt conveyors are used as transverse and delivery conveyors (DE 101 16 982 A1), as are, in fact, also used in cereal cutting mechanisms (see EP 1 055 359 A1).
On the other hand, one uses so-called corn mowing attachments or teeth as harvesting attachments ahead of field choppers, in order to harvest larger, stalk-like plants, especially corn, which can reach considerable heights of several meters. The corn mowing attachments usually comprise mowing and intake drums with lower cutting disks for the cutting off of the plants from the stubbles remaining in the ground, and overhead conveyor drums to remove the plants. The transverse transport takes place with separate transverse conveyors in the form of screw conveyors or belt conveyors (see, for example, DE 29 00 552 A1, DE 195 23 255 A1, or EP 1 008 291 A1), which are used as delivery conveyors, or with the backs of the mowing and intake drums, together with separate transverse conveyor drums and delivery conveyor drums (see EP 0 760 200 A1). The cutting disks cut the stems free and are therefore operated at a higher rotating speed than the conveyor drums, or they work together with stationary counter blades (see DE 10 2007 038 274 A1). The driving of the mowing and intake drums usually takes place with corresponding gears, which are driven by a shaft located in a transverse carrier.
Furthermore, in the state of the art, cutting mechanisms for cuttings are provided with rigid frames, that is, they cannot be folded into a transporting position, but rather are placed, as a whole, on a transport trailer, so as to pull them along, during transport, on a road behind the field chopper. Thus, a lot of time is lost in the attaching and detaching of the cutting mechanism for cuttings on the field chopper. Analogous statements are also valid for cereal cutting mechanisms with transverse conveyor belts, whose lateral parts can, in any case, be folded up manually for maintenance purposes (EP 2 695 510 A1). Even if the lateral parts would swivel up with the transverse belt conveyors, the attainable operating width would be rather limited: since the middle part with the delivery conveyor for conveying to the rear is relatively narrow, the wider lateral parts cannot be placed flat above the middle part. They can only be swiveled upward by 90°, which with larger widths of the lateral parts (and thus larger vertical dimensions in the transporting position) causes an operating width-limiting view restriction for the operator of the harvesting machine.
The corn mowing attachments are therefore structured in a relatively cumbersome manner—among other things, because each mowing and intake drum is provided with its own gear, including a corresponding housing. The cutting mechanism for the cuttings have, on the other hand, a simpler and lighter structure, but are also not suitable for the harvesting of excessively high plants. With expected climate changes, which lead to reduced precipitation, one can expect that, in certain areas of the world, increasingly, plants will be grown that can survive with relatively small amounts of water and are therefore not as large as corn, but nevertheless are too large to be harvested with a normal cutting mechanism for cuttings.